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Kidney disease remains very common today. For their diagnosis, various methods are used – moreover, more modern ones, for example, ultrasound and magnetic resonance imaging – are gradually replacing outdated and less informative ones. However, an x-ray examination of the kidneys, also known as urography, is still in demand due to the fact that it allows you to find out about changes in the structure of the organ and make the correct diagnosis.
Types of urography
There are several types of x-ray examination of the kidneys. Which method to use in each case, the urologist decides. The doctor must choose the best way to study the tissues of the kidneys and their functionality, depending on what kind of violations are present.
Survey urography
This procedure is prescribed to the patient if the doctor saw any signs of kidney disease. As a rule, it precedes all other, more complex studies. Plain urography is a regular x-ray of the part of the body where the kidneys are located.
This diagnosis cannot be called particularly informative, but it can be used to check the location of organs, as well as to identify large stones and some other problems. The indisputable advantage of this method is the fact that this study does not require any additional equipment, but it is carried out in any clinic. This method requires some preparation of the patient, which will be discussed below.
Plain urography does not use a contrast agent. This method gives an idea of the general picture of pathologies: it allows you to detect tumors, foreign bodies and large stones, as well as to identify changes in the anatomical location of the kidneys.
Plain urography allows the specialist to examine the structural state of the kidneys, starting from their upper section to the beginning of the bladder outlet duct. In addition, the doctor sees the bones of the pelvic region, and can also “as a first approximation” assess the condition and performance of the ureters and bladder.
Intravenous diagnostics
Intravenous urography is an X-ray examination that involves the use of a contrast agent. As a rule, it contains iodine. This solution is injected into the patient’s vein, provided that his bladder is empty. After that, several pictures are taken.
Preparation for intravenous urography is that the patient must empty the bladder. In total, there are three methods of intravenous urography: excretory, compression and infusion.
Excretory urography
Much like a review. The only difference between these diagnostic methods is that a contrast agent is used in the excretory study. The first picture is taken one to two minutes after its introduction, the second after five minutes, and the third after seven minutes. The study allows you to assess the intensity with which the bladder, ureters and renal pelvis are filled with fluid, and also allows you to evaluate the shape and structure of the kidneys, the location of stones and cystic tumors.
Compared to survey urography, the method is more informative, and the picture itself is more clear. Among the disadvantages of this technique is the possibility of an allergic reaction to the contrast agent. The doctor must necessarily find out if the patient suffers from an individual intolerance to any drugs. Even if the answer is negative, an allergy test is performed before the administration of the substance: 0,1 ml of a contrast agent solution is injected intradermally into the forearm. Then the doctor looks and evaluates the reaction.
Compression urography
This type is a more complex procedure. During it, the patient’s ureters are artificially clamped. The image is very clear, however, it is impossible to assess the condition of the ureters on them due to the fact that they are clamped. Therefore, experts recommend combining the compression method with the excretory one, so that the result is as informative as possible. A significant drawback of the procedure is the fact that this research method is very painful.
Infusion urography
It is usually prescribed for people with disabilities, as well as those who cannot move around. A contrast agent is injected through the catheter, and the study is performed on the patient in a supine state.
Depending on where exactly the contrast agent is injected, urography is retrograde and antegrade. In a retrograde study, a contrast agent is injected directly into the ureters under general anesthesia. After that, an overview urography is performed. This method makes it possible to study the ducts as clearly as possible.
In antegrade percutaneous urography, a contrast agent is injected through the skin into the upper part of the ureters. Going down them, the drug enables the doctor to study them properly. This method allows you to identify ruptures of the ureters, inflammation, neoplasms.
Each of the above methods has its own advantages and disadvantages. So, survey urography is fast and does not require the introduction of contrast, however, it cannot boast of high information content. With an excretory study, the image is not very accurate, but this method is simple and reliable. Compression urography also does not take much time, but the procedure is very painful. Infusion therapy is suitable for people with disabilities, but requires a lot of time due to the need to be under a drip. Retrograde and antegrade methods provide an exhaustive amount of information, but require general anesthesia.
Possibilities of survey urography
The main purpose of a review x-ray examination of the kidneys is to identify stones at different levels of the urinary system. These can be stones in the kidneys, bladder and ureters. However, it should be borne in mind that this method does not allow visualizing all types of stones, but only stones of urate and oxalate origin. Phosphate neoplasms in the pictures are most often invisible. In addition, the picture shows tuberculous foci and echinococcal cysts.
Also, using this method, the doctor can identify other pathological processes based on the data obtained. So, visualization of the kidney shadow will allow us to draw a conclusion about the size of the organ and its location. Based on the outlines of the lumbar muscle, one can judge the state of the fiber surrounding the kidneys. The doctor may also look at the lumbosacral spine, the hip joints, the lower edges of the ribs, and the pelvic bones.
Indications and contraindications
As noted above, survey urography is the first procedure to which a patient is referred for suspected pathological processes in the kidneys.
The indications for the study are:
- Congenital or acquired hydronephrosis of one or both kidneys.
- Stones in the urinary tract: in the tissues of the kidneys, bladder and ureters.
- The presence of foreign bodies in the urethra or in the lumen of the bladder.
- Lower back injuries, including torn back muscles.
- Tumors and other pathological foci (cysts, abscesses, etc.).
- Abnormalities in the development or location of the kidneys
At the same time, like any X-ray examination, the procedure has its own contraindications. So, the study is not carried out for pregnant women, patients suffering from radiation sickness, as well as for those who have had one kidney removed, and the functionality of the second is impaired, urography with the introduction of contrast is contraindicated.
In addition, they try not to refer patients to urography who have recently undergone a study of the gastrointestinal tract with barium suspension. This is because barium remaining in the body significantly impairs visualization of the kidneys and urinary tract. Therefore, the interval between studies should be at least a week in order for the barium suspension to completely leave the body.
What can a survey urography show
This diagnostic method, as noted above, is the initial stage of studying the condition of the kidneys. The doctor prescribes this procedure if he has suspicions about the dysfunction of the organ or the presence of certain pathological processes in it.
So, survey urography helps to identify:
- Benign or malignant neoplasms
- Changes in the structure of the organ tissue.
- Stones.
- Anomalies in the structure of the kidneys.
- Pyelonephritis, glomerulonephritis, hydronephrosis, kidney tuberculosis.
- Causes of blood in the urine.
- Possible complications after surgery.
How to take a picture
There are several principles that must be followed in order for the x-ray image to be as informative as possible and for the specialist to be able to diagnose the pathological process.
First of all, you should not take an x-ray of only one kidney. Doctors are aware of situations when changes in the site of the pain syndrome cannot be detected, and violations are detected in the opposite organ.
Качественным считается снимок, который максимально охватывает все структуры, являющиеся составляющими мочевыводящей системы: почки с мочеточниками и мочевой пузырь. Также на снимке должны присутствовать контуры одиннадцатого и двенадцатого ребер и верхний край лонного сочления. Использовать следует пленку размером тридцать на сорок сантиметров.
How is the procedure performed
Plain urography is a simple and not time-consuming procedure. Immediately after the patient enters the office, he is asked to remove jewelry and metal objects. After this, the patient is asked to lie on his back, a pillow is placed under his head. The x-ray beam is directed strictly perpendicular to the surface of the body, a few centimeters below the xiphoid process. Immediately at the time of the picture, the patient must hold his breath. This will help to avoid “double” images.
Special training
In order for the results to be as reliable as possible, the patient must prepare in advance for it.
So, it is often normal to visualize the processes that occur in the organs of the urinary system, sometimes swollen intestinal loops interfere. Therefore, it is extremely necessary to cleanse it of feces in advance.
To this end, patients are asked at least three days before the study to exclude from the diet food that can provoke flatulence. These are white flour bread, cereals and legumes, potato dishes, fruits and dairy products.
Dinner the night before should be light. Sit down at the table should be no later than six o’clock in the evening. On the day of the urography, it is better to refrain from breakfast.
It is recommended to start taking sorbents a few days before the procedure. An enema should be given in the morning before a kidney x-ray.
You should refrain from drinking large amounts of liquid. On the day of the study, you can drink a glass of unsweetened tea.
Features of the procedure for children
The method of conducting survey urography for children is no different from how adult patients are examined. It is not recommended to conduct a study of babies under the age of one month.
Note that when performing urography with a contrast agent, you should carefully calculate the amount of the drug for small patients.
However, even when conducting survey urography, which is absolutely painless, parents should prepare the child in advance and explain to him that he will not experience discomfort, and therefore should not be afraid.
Algorithm for describing the resulting image
The first step in describing the image is to study the state of the skeletal system. The thing is that pathological processes in the organs of the urinary system also affect the bones. So, for example, in chronic kidney disease, there is a so-called “compensatory scoliosis” of the spine in the direction of a healthy organ.
In the event that the patient has carefully prepared for the procedure, the shadows of the kidneys are clearly visible in the picture. The norm is the location of the left kidney at the level of the body of the twelfth thoracic and up to the second lumbar vertebrae, and the right kidney – from the first to the third bodies of the lumbar vertebrae. The fact that the right kidney is lower than the left is due to the fact that the liver presses on it.
Describing the shadows of the kidneys, the radiologist must indicate their shape, size and state of the contour, as well as comment on the density of the tissue of the organ.
The doctor is also interested in the condition of the lumbar muscles, their contours and symmetry. Any changes may indicate that an inflammatory process occurs in the retroperitoneal space or there are tumor foci.
As a rule, normal ureters are not visualized because they are hollow. If there is inflammation in their lumen or calculi are present, then the images show shadows that correspond to the location of the ureters.
The bladder is visible in the picture if concentrated urine is present in its lumen.
After the specialist has compiled a description of all the “natural” shadows and structures, he begins to study pathological and additional shadows, which may indicate dysfunction in the area being examined.
An alternative to survey urography
Despite its popularity, urography is considered an obsolete research method. Almost the same functions today are performed by ultrasound and MRI. They allow you to study all the internal organs, identify inflammatory processes, tumors and stones in the kidneys.